"One-Size-Fits-All" Diet Doesn't Exist, Say Researchers

(HealthDay News) — People have very different glycemic responses to the same food -- with some showing large blood glucose spikes even after eating supposedly healthy choices. Researchers said the findings, published in the Nov. 19 issue of Cell, underscore the message that there is no "one-size-fits-all" diet.

The findings are based on 800 Israeli adults who gave detailed information on their diet, lifestyle, and medical history. Over one week, they used a smartphone app to record all of their daily activities, including the food they ate, while glucose monitors kept track of their post-meal blood glucose changes. Each participant also gave a stool sample so the researchers could analyze their gut microbiome.

For the most part, study participants ate their normal meals, but the researchers did give them identical breakfasts so they could compare responses to the same meal following a fast. Overall, there was "immense" variation in glycemic responses to particular foods, depending on the person, according to co-researcher Eran Segal, Ph.D., of the Weizmann Institute in Rehovot, Israel. In one woman's case, for instance, the researchers suspect that tomatoes were a major culprit behind her blood glucose surges. That's based on the fact that tomatoes were part of every meal that caused her blood glucose to soar, Segal told HealthDay.

In a final step, the researchers created individual diets for 26 people, by feeding all of their data into an algorithm that predicted which foods would cause large spikes in blood glucose, and which would not. For some people, a "good" diet included foods like pizza and potatoes, the study authors said. For others, those foods were off the table. That study group spent one week on their personal "good" diet, and one week on a "bad" diet. On average, the researchers found, the good diets were tied to alterations in gut bacteria and lower post-meal blood glucose. Segal said that "we are now embarking on a series of follow-up studies that aim to unravel the long-term effects of the personalized diet on diabetes, weight management, and non-alcoholic fatty liver disease."